When comparing a ten-string guitar to a standard classical six-string guitar, I'm afraid that first analogy that occurs to me is that of the recent mutant frogs. These amphibians, as the result of nitrogen and phosphorus runoff from farms and ranches, have grown extra legs. The appearance of the ten-string guitar is similar in that it simply seems to have sprouted a few extra strings. Fortunately for music lovers, there is nothing unnatural about the ten-string guitar. While certain aspects of its appearance, especially the wider neck, may cause one to do an initial double take, the music of this instrument more than makes up for any startling facets to its form.

There are two main versions of ten-string guitar: the romantic and the modern. On the romantic ten-string, four or five of the strings are "floating basses," meaning that they are not fretted. A fret is a raised bar that runs width-wise across the instrument's neck; a fret usually spans the full width of the neck, but in the case of the floating basses, the fret stops short. On the modern ten-string, every string is fretted. The other major difference, of course, is that romantic ten-string guitars are no longer made. These instruments were manufactured from the late 18th to the mid-19th century. The age known as the Romantic Period spanned the years from 1820 to 1910, which explains the name of this guitar. Some romantic ten-string guitars are still known to exist today.

The modern ten-string guitar, like its counterpart, has a self-explanatory appellation. Its invention is credited to Narciso Yepes (1927-1997), an internationally famous Spanish guitarist who reached a point in his career at which he felt the six-string guitar no longer met his needs as an artist. The problem, he felt, was that this guitar lacked equilibrium; not physically, but in the resonance of the notes. While some notes would continue to sound even after the string's vibrations had been stopped, others would cease immediately. In order to correct this problem, Yepes determined to create a guitar that utilized uniform sympathetic resonance. Four bass strings were added and tuned so that they resonated equally in sympathy with any of the twelve notes on the chromatic scale. The effect is similar to that of a piano when the pedal is used.

The invention of the modern-ten string guitar occurred in 1963 in collaboration with Jose Ramirez, a Spanish guitar luthier. Since then, the ten-string guitar has become an established fact in the world of music. Although not common, it is certainly not unheard of, and it followers tend to be devout. Ten-string artists tout the instrument's accommodation of bass notes, which allows for accurate playing of music like that of Bach and his contemporaries (which was written for the Baroque lute). The ten-string permits such music to be played without having to transpose the bass notes.

The ten-string guitar, in addition to permitting the accurate performance of historical music, has also created new arena for the composition of modern music. Today's composers include Maurice Ohana, Leonardo Balada, Bruno Maderna and many others.